list of tuple

[steph bagnis]

Hi !
I'm a new python programmer and I'm searching some tools for working
with tuples's list.
For example I have a list like that :
[('+',4,3),('+', 3,9),'('+',5,6) ,('x',10),('x', 3)]
and I would like to get a list with just the tuple with index 0 '+' or
things like that. The question is : is it possible without doing a
loop ?

Thx

[Peter Hansen]

Re: list of tuple

steph bagnis wrote:
[color=blue]
> I'm a new python programmer and I'm searching some tools for working
> with tuples's list.
> For example I have a list like that :
> [('+',4,3),('+', 3,9),'('+',5,6) ,('x',10),('x', 3)]
> and I would like to get a list with just the tuple with index 0 '+' or
> things like that. The question is : is it possible without doing a
> loop ?[/color]

I guess it depends on what you consider a loop to be:

For example, a list comprehension should do the trick:

newlist = [x[0] for x in oldlist]

(This is equivalent to a for loop that goes through each item
in the old list, appending the 0-th element of each tuple to a new
list as it goes.)

-Peter

[Russell Blau]

Re: list of tuple

"Peter Hansen" <peter@engcorp. com> wrote in message
news:TJKdnUm2dc Exb1vdRVn-gQ@powergate.ca ...[color=blue]
> steph bagnis wrote:
>[color=green]
> > I'm a new python programmer and I'm searching some tools for working
> > with tuples's list.
> > For example I have a list like that :
> > [('+',4,3),('+', 3,9),'('+',5,6) ,('x',10),('x', 3)]
> > and I would like to get a list with just the tuple with index 0 '+' or
> > things like that. The question is : is it possible without doing a
> > loop ?[/color]
>
> I guess it depends on what you consider a loop to be:
>
> For example, a list comprehension should do the trick:
>
> newlist = [x[0] for x in oldlist]
>
> (This is equivalent to a for loop that goes through each item
> in the old list, appending the 0-th element of each tuple to a new
> list as it goes.)[/color]

If I understood the OP correctly, he wants to select those tuples that have
a '+' as the first item. So maybe he wants:

newlist = [x for x in oldlist if x[0] == '+']

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